func (b *planBuilder) buildSelect(sel *ast.SelectStmt) Plan {
// Detect aggregate function or groupby clause.
aggDetetor := &ast.AggFuncDetector{}
sel.Accept(aggDetetor)
var aggFuncs []*ast.AggregateFuncExpr
if aggDetetor.HasAggFunc {
extractor := &ast.AggregateFuncExtractor{AggFuncs: make([]*ast.AggregateFuncExpr, 0)}
// TODO: extract aggfuncs from having clause.
for _, f := range sel.GetResultFields() {
f.Expr.Accept(extractor)
// TODO: check error
}
aggFuncs = extractor.AggFuncs
// TODO: extract aggfuncs from having clause.
}
var p Plan
if sel.From != nil {
p = b.buildJoin(sel.From.TableRefs)
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
if sel.LockTp != ast.SelectLockNone {
p = b.buildSelectLock(p, sel.LockTp)
if b.err != nil {
return nil
}
}
if len(aggFuncs) > 0 {
p = b.buildAggregate(p, aggFuncs)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
} else {
if len(aggFuncs) > 0 {
p = b.buildAggregate(p, aggFuncs)
}
p = b.buildSelectFields(p, sel.GetResultFields())
if b.err != nil {
return nil
}
if sel.Where != nil {
p = b.buildFilter(p, sel.Where)
if b.err != nil {
return nil
}
}
}
if sel.OrderBy != nil {
p = b.buildSort(p, sel.OrderBy.Items)
if b.err != nil {
return nil
}
}
if sel.Limit != nil {
p = b.buildLimit(p, sel.Limit)
if b.err != nil {
return nil
}
}
return p
}
